<section>
  <h4>
    single selection, allow clear value
    <!--单选框开启清除选项功能-->
  </h4>
  <div class="row">
    <div class="col-md-5">
      <d-select [placeholder]="'Input'" [options]="options" [allowClear]="true" [(ngModel)]="value"></d-select>
    </div>
    <div class="col-md-1">
      <d-button bsStyle="common" (btnClick)="value = null"
        >reset value by reset ngModel value
        <!--通过ngModel清空值--></d-button
      >
    </div>
  </div>
</section>
